Description:
------------
Can anyone explain the bizarre behavior of this code?

<?
$text = "Lorem ipsum dolor sit amet,\n\rconsetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt";
$size = 15;
$fontfile = "Cyberbit.ttf"; // from ftp://ftp.netscape.com/pub/communicator/extras/fonts/windows/Cyberbit.ZIP
print_r(imageftbbox($size, 0, $fontfile, $text, array()));
echo '<br />';
print_r(imageftbbox($size, 0, $fontfile, $text, array()));
?>

Output:
Array ( [0] => -1 [1] => 5 [2] => 598 [3] => 5 [4] => 598 [5] => -33554432 [6] => -1 [7] => -33554432 )
Array ( [0] => -1 [1] => 37 [2] => 598 [3] => 37 [4] => 598 [5] => -16 [6] => -1 [7] => -16 )

Particulars:
Freetype 2.0.4
GD 2.0.9
PHP 4.3.1

What's going on?  The [5] and [7] values of the output array (Y positions of the upper corners of the bounding box) are anomalous the first time the imageftbbox function is called.  When the function is called again in an identical manner, the values are good.

imagettfbbox does not exhibit this behavior on my system.

If this is a known bug, cursory searches haven't brought up anything about it.

Help!

All the best,
Robert K S

Reproduce code:
---------------
<?
$text = "Lorem ipsum dolor sit amet,\n\rconsetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt";
$size = 15;
$fontfile = "Cyberbit.ttf"; // from ftp://ftp.netscape.com/pub/communicator/extras/fonts/windows/Cyberbit.ZIP
print_r(imageftbbox($size, 0, $fontfile, $text, array()));
echo '<br />';
print_r(imageftbbox($size, 0, $fontfile, $text, array()));
?>

Expected result:
----------------
Output:
Array ( [0] => -1 [1] => 37 [2] => 598 [3] => 37 [4] => 598 [5] => -16 [6] => -1 [7] => -16 )
Array ( [0] => -1 [1] => 37 [2] => 598 [3] => 37 [4] => 598 [5] => -16 [6] => -1 [7] => -16 )

Actual result:
--------------
Output:
Array ( [0] => -1 [1] => 5 [2] => 598 [3] => 5 [4] => 598 [5] => -33554432 [6] => -1 [7] => -33554432 )
Array ( [0] => -1 [1] => 37 [2] => 598 [3] => 37 [4] => 598 [5] => -16 [6] => -1 [7] => -16 )